Extra-cortical clamp with detachable tensioning tool for internal fixation of bone fractures



Nov. 11, 1969 A. SAMPSON 3,477,429

EXTRA-CQRTICAL CLAMP WITH DETACHABLE TENSIONING TOOL FOR INTERNAL FIXATION OF BONE FRACTURES 2 Sheets-Sheet 1 Filed June 30, 1967 mvmox ARNOLD SAMPSON M d- M334 ATTORNEY- Nov. 11, 1969 A. SAMPSON 3,477,429

EXTRA-CORTICAL CLAMP WITH DETACHABLE TENSIONING TOOL FOR INTERNAL FIXATION OF BONE FRACTURES Filed June 50, 1967 2 Sheets-Sheet 2 FIG. 4

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INVENI'OR ARNOLD SAMPSON United States Patent 3,477,429 EXTRA-CORTICAL CLAMP WITH DETACHABLE TENSIONING TOOL FOR INTERNAL FIXATION OF BONE FRACTURES Arnold Sampson, Pittsburgh, Pa., assignor to The Sampson Corporation Filed June 30, 1967, Ser. No. 650,348 Int. Cl. A61b 17/00; A61f 5/04 US. Cl. 128-92 12 Claims ABSTRACT OF THE DISCLOSURE A clamp for internal fixation of bone fractures including a two-jaw implant head and an installation and tensioning tool adapted to be secured to the implant head during reduction and internal fixation of the fracture. Power means on thetool causes movement of the implant head jaws with respect to each other. Locking means on the implant head retains the positioning of the jaws and the installation and tensioning tool is then released and removed leaving the implant head permanently secured about the fracture.

This invention relates to a new and useful device for open reduction and internal fixation of fractures of long bones. More particularly, the invention relates to a clamping device specifically adapted to the internal fixation of fractures of long bones by open reduction, and wherein the clamping device implant head, which is used to reduce and position the fracture, is locked in place, and is the structure which obtains and maintains internal fixation at the fracture site.

Internal fixation of long bone fractures has been practiced for many years throughout the world. With the advent of improved non-reactive metals and antibiotics its use inevitably will become more widespread.

Among the various methods and apparatus conventionally used are screw fixation, bone plate and screw fixation, Parham Band fixation, Intra-Medullary pin and nail fixation and compression instrumentation in conjunction with bone plate and screw fixation.

None of the previously mentioned methods have been wholly successful, and each 'has certain inherent drawbacks. With all of the prior arts disclosed, each method can only be used for certain types of anatomic fractures. Screw fixation and Parham Band fixation can only be used for oblique or spiral fracture's, but are ineffective for transverse and comminuted fractures. Intra-Medullary pins and nails and bone plates and screws and compression instrumentation devices are effective for transverse fractures, less effective for oblique or spiral fractures and almost useless for severely comminuted or bag of bones fractures.

A further objection is noted with the prior art methods disclosed, that because of the complex nature of these techniques a high degree of surgical skill is required to effectively apply and position these internal fixation devices. In addition, a temporary holding device such as a Lowman Clamp must be utilized until the definitive internal fixation device is positioned on the fracture site. Not infrequently, due to improper or inadequate positioning of the definitive fixation device, when the Lowman Clamp is removed, the good reduction is lostand the procedure must be repeated.

A further objection is noted that with most of the prior art methods disclosed, extensive dissection of soft tissue structures and periosteum and wide exposure of the fracture site is necessary. The operation is, therefore, time consuming. These factors enhance the possibility of wound infection, osteomyelitis and non-union of fractures.

The extra-cortical clamp herein disclosed obviates the difiiculties inherent in the prior art methods and provides an internal fixation means which more easily, quickly and effectively positions and maintains fracture site stability, and is effective for all types of fractures.

Another object of this invention is to avoid the disadvantages common in the prior art of internal fixation by providing a claimping device for holding the bone fragments in positive alignment and preventing any movement whether lateral, torsional, or longitudinal, and without placing undue pressure upon the bone surface.

Yet another object of this invention is to provide a cortical clamp for internal fixation of the fractures of the long bones such as the femur, tibia, fibula, radius, ulna, clavicle, and ribs.

Still another object of this invention is to provide a clamping device which may be readily applied by any surgeon, even one with minimal orthopedic background and which is formed of two separate separable sections, one of which is a tool useful in inserting and tightening the implant head or clamp, which remains about the bone and about which the wound is closed.

Another object of this invention is to provide a cortical clamp which obtains and maintains good anatomic reduction of a fracture and which can be applied with minimal surgical dissection of soft tissues and especially the periosteum.

A further object of this invention resides in the provision of a new type of clamping device for reducing fractures which will in many cases, obviate the necessity for plaster casts and which will insure good apposition of the fragments and firm fixation thereof to such a degree that the patient may in many instances use the fractured limb in the usual manner while the bone fragments are in the process of uniting.

An object of this invention is to provide a novel cortical clamp arrangement which is of genrally simple construction, has a minimum number of parts, and is safe and efficient in use and which requires a minimum of maintainence.

The above and other objects and features of the invention will become more apparent from a consideration of the following disclosure.

An extra-cortical clamp device in accordance with the present invention includes an installation and tensioning tool which is fixed to an implant head during reduction of the fracture. The installation tool is provided with power transmission means to initially tighten the implant head about the fracture to reduce the fragments and to fix them in proper anatomical position. Thereafter, the implant head is locked in position and the installation and tensioning tool is removed from the implant head whereafter the wound is closed about the implant head.

In order that the general principles ofthis invention may be readily understood, reference should be had to the following detailed description taken in conjunction with the accompanying drawings which illustrate the best mode now contemplated by me for carrying out my invention:

FIGURE 1 is a perspective view showing the implant head and installation and tensioning tool assembled about a fractured tibia;

FIGURE 2 is a perspective view similar to FIGURE 1, but showing the implant head and installation and tensioning tool in position after tightening of the clamp about the tibia and showing the bone sections in proper anatomical position;

FIGURE 3 is a perspective similar to FIGURE 2, but showing the installation and tensioning tool withdrawn from the implant head;

FIGURE 4 is a bottom plan view of the implant head joined to the installation and tensioning tool which the operating knob cut away;

3 FIG. 5 is a vertical sectional view taken along the lines 5--5 of FIGURE 4;

FIGURE 6 is a section taken along lines 66 of FIG- URE 5;

FIGURE 7 is a section taken along lines 7-7 of FIG- URE 5;

FIGURE 8 is a sectional view through lines 88 of FIGURE 5, but showing the implant head separated from the installation and tensioning tool and showing the spring arms in their open position; and

FIGURE 9 is a perspective view of a modified form of implant head.

Reference is now made specifically to the drawings, wherein like reference numerals designate similar parts throughout the several views and wherein the cortical clamp assembly constituting the subject matter of this invention is designated generally at 10.

The cortical clamp comprises two component structures namely, the implant head shown generally at 11 and the installation and tensioning tool 12. The cortical clamp is preferably fabricated in whole or in part from a controlled low carbon content stainless steel such as Zernaloy or AISI 316. This material may be cast, precision machined, polished, electro-polished and passivated. It should be understood, however, that any conventional desired material may be used in the construction of the cortical clamp.

The implant head 11 comprises a frame jaw 13 which serves as the stationary portion of the head. This jaw has a curved end face as shown at 14 which extends upwardly at a right angle to the base portion of the frame jaw and curves back at its upper extremity. The curved jaw end face is of a width considerably greater than the base portion of the frame jaw, and the end face is provided preferably with a plurality of apertures 15. The inner surface of the curved end face is formed with a plurality of bone engaging projections 16 shown spaced in two rows. These projections are preferably of pyramidal configuration as shown in FIGURE 4, although other shapes may be employed. The base of the frame jaw 13 is bifurcated as shown at 17 for a purpose later described. The upper face of each of the legs of the bifurcated portions are serrated at 18 to provide locking ridges. The side faces of the bifurcated portion of the frame jaw are provided with tool locking holes 19 as shown in FIGURE 3 for cooperation with the locking device on the installation and tensioning tool 12 as hereinafter described in greater detail.

The bottom face of the base portion of the bifurcated frame jaw has undercut flanges 20* thereon. These flanges cooperate with a rectangular slide nut 21 as shown in FIGURE 4.

The mating companion portion of the implant head consists of a trolley jaw 22 which in use is adapted to be moved into adjusted position with respect to the frame jaw 13. The trolley j-aw includes an integral base or boss 23 having locking serrations 24 on the bottom surface thereof adapted to cooperate with the locking serrations 18 of the frame jaw. The end face 25 of the trolley jaw extends generally vertically, although it is bent inwardly adjacent its top edge and pyramidal projections 26 are provided as shown in FIGURE 4 for engagement with the bone. A fiat boss or horizontal bearing surface 27 is provided at the top of the trolley jaw base 23 and has a drilled recess therein for reception of the locking bolt 28. Tool locking holes 29 are provided on each side of the trolley jaw base for cooperation with locking means provided on the installation and tensioning tool 12 as hereinafter described.

From an examination of FIGURES 1 through 3, 5, and 6, it will be apparent that when the bolt 28' is loosened within the rectangular slide nut 21, that the trolley jaw may be moved with respect to the frame jaw so that the locking serrations will ride over one another. Once the implant head is in its proper adjusted position 4 such as about the bone portions A, B in FIGURE 1, th bolt 28 may be tightened either by means of a screwdriver or an Allen wrench, so that the frame jaw and the trolley jaw are drawn together through the rectangular slide nut 21 thereby tightly engaging the locking serrations 18 and 24 preventing any further movement of the frame jaw and trolley jaw with respect to each other.

It will be understood that the function of the cortical clamp arrangement is to properly tension the implant head about a bone fracture so that the portions A and B are drawn together in proper fixation as shown in FIG- URE 2..Once the proper reruction has taken place, the locking bolt 28 may be applied so that further movement of the jaws will be impossible. It will be understood that the implant head is designed to remain in place about the fracture after reduction and may remain about the patients bone permanently, or if desired, at a later date may be removed during surgery. It will be apparent that the materials used for the implant head must be such as to be totally unelfected by body fluids and tissues even though exposed to the same for prolonged periods of time.

In order to properly install and tension the implant head an installation and tensioning tool 12 is provided. This tool includes an elongated base frame 31 and an elongated trolley frame 32 superimposed thereon and adapted for movement with respect thereto. The base frame 31 is adapted to be removably connected to the frame jaw of the implant head and the trolley frame 32 is adapted to be removably connected to the trolley jaw. In this manner, movement of the trolley frame with respect to the base frame will result in movement of the trolley jaw with respect to the frame jaw.

The base frame includes a guide channel 33 as shown in FIGURES 3 and 4. Formed either integral therewith or as separate members attached thereto are the side frames 34 which extend somewhat forwardly of the base frame, see FIGURE 8. It should be noted that the distance between the inner faces of the respective side frames is slightly greater than the outer width of the base of the frame jaw 13 to allow the bifurcated frame jaw portions to be received between the side frames 34. Side frame apertures 35 of the same size and shape as the apertures 19 in the frame jaw are provided.

The base frame has upstanding therefrom and formed integral therewith at its rear end an end boss 36. The boss is axially bored and tapped and has a longitudinal opening along its top surface so as to provide a partially threaded bore for reception of an adjusting jack screw as later described. The trolley frame 32 is of generally elongated configuration, although somewhat shorter than the base frame 31 and has formed at its rearward end an upstanding enlargement 37. A vertical bore 38 extends partially through the enlargement and communicates with the end face of the enlargement by means of a horizontal bore 39 forming a narrow keyway 40.

The trolley frame is adapted to be moved fore and aft by means of a jack screw 41 which is threaded for a major portion of its length; the threaded portion being received within the threaded bore of the end boss 36 of the base frame. As can be seen from a study of FIG- URE 5, the end portion of the jack screw 41 is unthreaded and terminates in a ball fitting 42, having a reduced diameter shaft portion connecting to the unthreaded portion of the jack screw. The ball 42 is adapted to be rotatably received within the vertical bore 38 with the reduced diameter portion received within the narrow keyway 40. A knurled operating knob 43 is secured or integrally formed on the free end of the jack screw for manual operation.

In order to insure proper alignment betwen the trolley frame and base frame and to achieve accuracy and precision in movement, a guide pin 44 depends from the bottom face of the trolley frame and may be secured thereto by a threaded connection or Otherwise as desired.

Pin 44 extends into the guide channel 33 of the base frame as can be seen in FIGURES 4 and 5 and terminates in a rectangular retaining plate 45, the ends of which overlap the bottom of the guide channel 33. The diameter of guide pin 44 is chosen so 'as to be slightly less than the width of the guide channel 33 and hence serves to maintain proper alignment between the "trolley frame and base frame. An integral cross piece 46 extends between the sides of the base frame and serves as a limit stop for forward movement of the trolley frame over the base frame. It will be seen that the guidepin 44 will contact the forward edge of the cross piece 46 thereby limiting movement. .In order to insure proper alignment, an auxiliary guide pin 47 depends from the bottom of the trolley frame 32 somewhat rearwardly of the guide pin 44.

In a manner similar to the base frame, the trolley frame is provided with extending side frames 48 each of which are provided with side frame apertures 49.

Actual interconnection between both the trolley frame and base frame with the respective trolley jaw and frame jaw takes place through the intermediary of leaf spring arrangements. A pair of base frame leaf springs are shown at 50 and are attached to the base frame 31 by means of attachment screws 51. These leaf springs extend along the sides of the side frames 34 and are preferably of the same length. Attachment or locking pins 52 are formed integral with or secured on the inner faces of each of the leaf springs 50 adjacent their forward ends and are of such a diameter and length as to be adapted to extend into the base frame side arm apertures 35 and the frame jaw apertures or tool locking holes 19. Movement of the base frame leaf springs 50 with their locking pins is through means of a spring release and compressing bolt 53 extending through the leaf springs and the base frame. As shown in FIGURE 7, the fixed end of the spring release and compressing bolt is provided with a hex end 54 adapted to fit within a mating recess in the spring 50 to prevent rotation of the bolt. A knurled cap nut 55 is threaded on the free end of bolt 53. It will be obvious from a study of FIG- URE 8 that tightening of the knurled cap nut 55 will result in compression of the leaf springs 50 thereby mov ing the locking pins 52 into the apertures 35 in the side frames 34 of the base frame. If the frame jaw 13 of the implant head is in proper position between the bifurcated side frames 34, the pins 52 will extend into the locking holes 19 thereof, thereby securing the frame jaw to 'the base frame.

The trolley frame is provided with similar locking mechanism. A pair of leaf springs 56, equivalent to the leaf springs 50, are coextensive with the side frames 48, and are attached to the trolley frame by means of attaching screws 57. Securing or looking pins 58 extend inwardly from the outer ends of the trolley frame leaf springs. A spring release and compressing bolt 59 is provided for retraction and controlled extension of the trolley frame leaf springs and is provided with a hexagonal end 60 as shown in FIGURE 7. A knurled cap nut 61 controls the retraction and extension in a manner similar to the cap nut 55. It will be apparent that the trolley frame may be securely attached to the trolley jaw of the implant head by bringing the trolley jaw base 23 between the extending ends of the trolley frame side frames 48 so that the holes 29 and 49 are in proper alignment. Thereafter, tightening of the cap nut 61 will cause the locking pins 58 to move into the holes thereby securing the trolley jaw to the trolley frame.

The operation of the cortical clamp will be apparent by reference to FIGURES 1 through 3. In FIGURE 1, the clamp is shown in assembled position with the bolt 28 loosened so that the trolley jaw of the implant head is free to move with respect to the frame jaw 13. The trolley frame and base frame are secured by means of the locking pins passing through the apertures of both the frame jaw and trolley jaw of the implant head. With the jack screw turned all the way out so that the jaws of the implant head are fully extended, the entire clamping arrangement is placed in'position about the fracture (FIGURE 1). It will, of course, be apparent that the amount of periosteurn to be stripped will be a minimum and will be limited to the size of the implant head jaws chosen for the particular operation. Once the jaws of the implant head are in proper position, the jack screw 41 will be turned by means of the adjusting knob 43 causing a forward thrust on the trolley frame thereby moving the trolley jaw toward the end face 14 of the frame jaw. Turning of the operating knob will continue until such time as the bone sections A and B are in proper anatomical position and the fracture has been reduced. This condition is shown clearly in FIGURE 2.

Once proper positioning of the bone fragments has been achieved by adjustment of the jack screw 41, the locking bolt 28 on the implant head is securely tightened by means of a screwdriver or Allen wrench so that the frame jaw and the trolley jaw of the implant head are secured tightly together through the locking serrations thereon. The cap nuts 55 and 61 on the base frame and trolley frame respectively are then loosened so as to disengage the locking pins 52 and 58 from engagement with the implant head locking holes 119 and 29. Thereafter, the entire installation and tensioning tool 12 may be withdrawn rearwardly as shown in FIGURE 3. The wound may then be surgically closed and the procedure terminated.

In FIGURE 9, I have illustrated a modification of the implant head, although it is to be understood that many other forms may be provided based upon specific indications for certain of the bones. The modified implant head of FIGURE 9 is shown generally at 111 and includes a frame jaw 113 having a curved jaw end face 114. The frame jaw is bifurcated in the same manner as the implant head 11 of the preferred embodiment. In this case, serrations 115 are provided along the entire inner face of the curved jaw end face 114. Locking aperatuers 119 are formed in the bifurcated sides of the frame jaw. A trolley jaw 122 is provided with serrations 1323 along its inner face and is also formed with a locking aperture 124. Operation and function of the modified implant head 111 is similar in all respects to the implant head 11.

Among the post-operative advantages attributed to the instant invention are that splinting and casting of the fracture site is usually minimized resulting in less muscle attrophy and joint stiffness, due to early mobilization. Additionally, rapid healing of the fracture is due to the minimal disturbance and stripping of the periosteum. All of these factors contribute to the ease of handling patients both in the hospital, in transport, and during recuperation at home. It is believed that these factors have important implications in the care and rehabilitation of battle casualities in the military services.

What I claim as my invention and desire to protect by Letters Patent of the United States is:

1. An extra-cortical clamp for reducing bone fractures and maintaining internal fixation throughout healing of the fracture comprising in combination, an implant head having a pair of opposed rigid parallel jaws adapted to be moved relative to each other about a fractured bone, means to lock said pair of opposed jaws in a selected position of compression about a bone, an installation and tensioning tool having a pair of parallel frame members, means removably connecting one of said frame members to one of said implant head jaws, means removably connecting the other of said frame members to the other of said implant head jaws, said frame members when connected to said implant head jaws extending therefrom in a direction parallel to the direction of jaw movement, and mechanical force transmission means for moving one of said frame members with respect to the other and parallel thereto so that the implant head jaw associated therewith will be moved with respect to the other implant head jaw when the same are unlocked.

2. A clamp as defined in claim 1, wherein the mechanical force transmission means comprises a jack screw threadedly received through one of said frame members and having one end thereof in engagement with the other of said frame members.

3. A clamp as defined in claim 1, wherein the inner faces of each of said opposed jaws are provided with a plurality of sharp pointed bone engaging projections adapted to penetrate the periosteum and a portion of the cortex of the bone.

4. A clamp as defined in claim 1, wherein the means to lock said pair of opposed jaws comprises a generally flat surface extending from each of said jaws in superposed relation, locking serrations on said fiat surfaces and bolt means adapted to draw said flat surfaces together into locking relationship.

5. An extra-cortical clamp for reducing bone fractures comprising in combination, an implant head having a pair of opposed jaws adapted to be moved relative to each other about a fractured bone, means to lock said pair of opposed jaws in a selected position of adjustment, an installation and tensioning tool having a pair of frame members, means removably connecting one of said frame members to one of said implant head jaws, means removably connecting the other of said frame members to the other of said implant head jaws, and mechanical force transmission means for moving one of said frame members with respect to the other so that the implant head jaw associated therewith will be moved with respect to the other implant head jaw when the same are unlocked, said means removably connecting each of the frame members to its associated implant head jaw comprising at least one looking hole in each implant head jaw, at least one leaf spring secured at one end to one of said frame members, said leaf springs being normally biased away from said respective frame member, locking projection means on the other end of said leaf springs adapted to be received in locking arrangement within said locking hole of the respective implant head jaw when said leaf spring associated therewith is compresed, and means to selectively compress and release said leaf springs.

6. A clamp as defined in claim 5, wherein each implant head jaw has an integral extension thereon, said extensions being superposed in mating relation and said locking holes being formed in said extensions.

7. A clamp as defined in claim 6, wherein the means to lock said pair of opposed jaws comprises a plurality of locking serrations on the mating surfaces of said jaw extensions, and bolt means adapted to draw said extensions together into locking relationship.

8. An extra-cortical clamp for internal fixation of bone fractures comprising in combination, an implant head having a pair of opposed normally relatively movable jaws adapted to be placed about a fractured bone, means to lock said jaws in a selected position of adjustment, locking apertures in each of said jaws, an installation and tensioning tool including a pair of superposed relatively movable frame members, mechanical means for moving one of said frame members relative to the other, a leaf spring extending along each of the sides of each of the frame members, the rearward end of each leaf spring being secured to the respective frame member, said leaf springs being normally biased away from the sides of the frame members but adapted to lie against the sides when compressed, a locking projection on the inner face of each of said leaf springs adjacent the forward end thereof, and means on each frame member to selectively compress and release the leaf springs associated therewith, whereby said locking projections may be brought toward each other by said compressing means to engage in the locking apertures of said jaws to secure the same to the frame members for movement in conjunction therewith.

9. A clamp as defined in claim 8, wherein the mechanical means for moving one of said frame members relative to the other comprises an upstanding boss on one of said frame members, said boss being axially threaded, and a jack screw threadedly received within said boss and having its forward end connected to the other of said frame members.

10. A clamp as defined in claim 8, wherein the means to compress and release the leaf springs on each frame member comprises a bolt extending through said leaf springs and frame member, means restraining said bolt from rotation with respect to said leaf springs and frame member, and a cap nut received on the free end of said bolt and adapted to be screwed down on said bolt thereby drawing said leaf springs against said frame member.

11. A clamp as defined in claim 8, wherein one of said frame members is provided with limit stop means to restrict the amount of movement of one frame member with respect to the other.

12. An extra-cortical clamp for reducing bone fractures and maintaining internal fixation throughout healing of the fracture comprising in combination, an implant head having a pair of opposed rigid parallel jaws adapted to be moved relative to each other about a fractured bone, means to lock said pair of opposed jaws in a selected position of compression about a bone, including screw means passing through one of said implant head jaws and being threadedly received by said other implant head jaw, an installation and tensioning tool having a pair of parallel frame members, means removably connecting one of said frame members to one of said implant head jaws, means on the other of said frame members removably in contact with the other of said implant head jaws to restrain the movement thereof, said frame members when connected to said implant head jaws extending therefrom in a direction parallel to the direction of jaw movement, and mechanical force transmission means for moving one of said frame members with respect to the other and parallel thereto so that the implant head jaw associated therewith will be moved with respect to the other implant head jaw when the same are unlocked.

References Cited UNITED STATES PATENTS 1,308,799 7/ 1919 Masland. 1,985,108 12/1934 Rush s 128346 2,427,128 9/ 1947 Ettinger. 3,227,156 1/1966 Gauthier 1282O OTHER REFERENCES General Catalog Fracture Equipment, Splints, Orthopedic Appliances (De Puy), De Puy Mfg. Co., Inc., Warsaw, Ind., 1964, received in Group 335, May 12, 1966, page 68 relied upon.

RICHARD A. GAUDET, Primary Examiner R. L. FRINKS, Assistant Examiner U.S. Cl. X.R. 128-346 

